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Network Working Group                                           G. Klyne
Internet-Draft                                                Clearswift                                              Nine by Nine
Expires: December 4, 2002                                   June 5, 2002 August 19, 2004                                        J. Palme
                                                Stockholm University/KTH
                                                       February 19, 2004


              Registration of mail and MIME header fields
                       draft-klyne-hdrreg-mail-01
                       draft-klyne-hdrreg-mail-02

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
   groups may also distribute working documents as Internet-
   Drafts. Internet-Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time. It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

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   http://www.ietf.org/ietf/1id-abstracts.txt. http://
   www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on December 4, 2002. August 19, 2004.

Copyright Notice

   Copyright (C) The Internet Society (2002). (2004). All Rights Reserved.

Abstract

   This document defines the initial IANA registration for some permanent
   mail and MIME message header fields. fields, per [[[RFC XXXX]]] [1].

Discussion of this document

   Please send comments to <ietf-822@imc.org>. To subscribe to this
   list, send a message with the body 'subscribe' to <ietf-822-
   request@imc.org>.
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Internet-Draft          Mail       Mail/MIME header registration               June 2002         February 2004


Table of Contents

   1.     Introduction . . . . . . . . . . . . . . . . . . . . . . .   7   4
   1.1    Structure of this document . . . . . . . . . . . . . . . .   7   4
   1.2    Document terminology and conventions . . . . . . . . . . .   7   4
   2.     Registration templates . . . . . . . . . . . . . . . . . .   7   4
   2.1    Permanent mail header field registrations  . . . . . . . .   4
   2.1.1  Header field: Date . . . . . .   7
   2.1.1  Date: header . . . . . . . . . . . . . .   6
   2.1.2  Header field: From . . . . . . . . .   9
   2.1.2  From: header . . . . . . . . . . .   7
   2.1.3  Header field: Sender . . . . . . . . . . . .  10
   2.1.3  Sender: header . . . . . . .   7
   2.1.4  Header field: Reply-To . . . . . . . . . . . . . . .  11
   2.1.4  Reply-To: header . . .   8
   2.1.5  Header field: To . . . . . . . . . . . . . . . . . .  11
   2.1.5  To: header . . .   8
   2.1.6  Header field: Cc . . . . . . . . . . . . . . . . . . . . .  12
   2.1.6  Cc: header   9
   2.1.7  Header field: Bcc  . . . . . . . . . . . . . . . . . . . .   9
   2.1.8  Header field: Message-ID . . . .  12
   2.1.7  Bcc: header . . . . . . . . . . . . .  10
   2.1.9  Header field: In-Reply-To  . . . . . . . . . .  13
   2.1.8  Message-ID: header . . . . . .  10
   2.1.10 Header field: References . . . . . . . . . . . . . .  13
   2.1.9  In-Reply-To: header . . .  11
   2.1.11 Header field: Subject  . . . . . . . . . . . . . . . .  14
   2.1.10 References: header . .  11
   2.1.12 Header field: Comments . . . . . . . . . . . . . . . . . .  14
   2.1.11 Subject: header  12
   2.1.13 Header field: Keywords . . . . . . . . . . . . . . . . . .  12
   2.1.14 Header field: Resent-Date  . . .  15
   2.1.12 Comments: header . . . . . . . . . . . . .  13
   2.1.15 Header field: Resent-From  . . . . . . . .  15
   2.1.13 Keywords: header . . . . . . . .  13
   2.1.16 Header field: Resent-Sender  . . . . . . . . . . . . .  16
   2.1.14 Resent-Date: header . .  14
   2.1.17 Header field: Resent-To  . . . . . . . . . . . . . . . . .  16
   2.1.15 Resent-From: header  14
   2.1.18 Header field: Resent-Cc  . . . . . . . . . . . . . . . . .  15
   2.1.19 Header field: Resent-Bcc . .  17
   2.1.16 Resent-Sender: header . . . . . . . . . . . . . . .  15
   2.1.20 Header field: Resent-Message-ID  . . .  18
   2.1.17 Resent-To: header . . . . . . . . . .  16
   2.1.21 Header field: Return-Path  . . . . . . . . . .  18
   2.1.18 Resent-Cc: header . . . . . .  16
   2.1.22 Header field: Received . . . . . . . . . . . . . .  19
   2.1.19 Resent-Bcc: header . . . .  16
   2.1.23 Header field: Disposition-Notification-To  . . . . . . . .  17
   2.1.24 Header field: Disposition-Notification-Options . . . . . .  17
   2.1.25 Header field: Original-Recipient . .  19
   2.1.20 Resent-Message-ID: header . . . . . . . . . . .  18
   2.1.26 Header field: Originator . . . . .  20
   2.1.21 Return-Path: header . . . . . . . . . . . .  18
   2.1.27 Header field: PICS-Label . . . . . . .  20
   2.1.22 Received: header . . . . . . . . . .  19
   2.1.28 Header field: Encoding . . . . . . . . . . .  21
   2.1.23 Content-features: header . . . . . . .  19
   2.1.29 Header field: List-Archive . . . . . . . . . .  21
   2.1.24 Content-Disposition: header . . . . . .  20
   2.1.30 Header field: List-Help  . . . . . . . . .  22
   2.1.25 Disclose-Recipients: header . . . . . . . .  20
   2.1.31 Header field: List-ID  . . . . . . .  22
   2.1.26 Originator: header . . . . . . . . . . .  21
   2.1.32 Header field: List-Owner . . . . . . . . .  23
   2.1.27 PICS-Label: header . . . . . . . .  21
   2.1.33 Header field: List-Post  . . . . . . . . . . . .  24
   2.1.28 Content-Language: header . . . . .  22
   2.1.34 Header field: List-Subscribe . . . . . . . . . . . .  24
   2.1.29 Content-Alternative: header . . .  22
   2.1.35 Header field: List-Unsubscribe . . . . . . . . . . . .  25
   2.1.30 Encoding: header . .  23
   2.1.36 Header field: Message-Context  . . . . . . . . . . . . . .  23
   2.1.37 Header field: DL-Expansion-History . . . . .  25
   2.1.31 Content-MD5: header . . . . . . .  24
   2.1.38 Header field: Alternate-Recipient  . . . . . . . . . . . .  26
   2.1.32 List-Archive: header  24
   2.1.39 Header field: Original-Encoded-Information-Types . . . . .  25
   2.1.40 Header field: Content-Return . . . . . . . . . . . . . .  26
   2.1.33 List-Help: header .  25
   2.1.41 Header field: Generate-Delivery-Report . . . . . . . . . .  26



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   2.1.42 Header field: Prevent-NonDelivery-Report . . . . . . . . .  27
   2.1.34 List-ID: header  26
   2.1.43 Header field: Obsoletes  . . . . . . . . . . . . . . . . .  27
   2.1.44 Header field: Content-Identifier . . . .  28
   2.1.35 List-Owner: header . . . . . . . . .  27
   2.1.45 Header field: Delivery-Date  . . . . . . . . . . .  28
   2.1.36 List-Post: header . . . .  28
   2.1.46 Header field: Expiry-Date  . . . . . . . . . . . . . . . .  29
   2.1.37 List-Subscribe: header  28
   2.1.47 Header field: Reply-By . . . . . . . . . . . . . . . . . .  29
   2.1.38 List-Unsubscribe: header
   2.1.48 Header field: Importance . . . . . . . . . . . . . . . . .  30
   2.1.39 MIME-Version: header  29
   2.1.49 Header field: Incomplete-Copy  . . . . . . . . . . . . . .  30
   2.1.50 Header field: Priority . . . . .  30
   2.1.40 Content-ID: header . . . . . . . . . . . . .  30
   2.1.51 Header field: Sensitivity  . . . . . . .  31
   2.1.41 Content-Description: header . . . . . . . . .  31
   2.1.52 Header field: Language . . . . . .  31



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   2.1.42 Content-Transfer-Encoding: header . . . . . . . . . . . .  32
   2.1.43 Content-Type: header . .
   2.1.53 Header field: Conversion . . . . . . . . . . . . . . . . .  32
   2.1.44 Disposition-Notification-To: header  . . .
   2.1.54 Header field: Conversion-With-Loss . . . . . . . .  33
   2.1.45 Disposition-Notification-Options: header . . . .  33
   2.1.55 Header field: Message-Type . . . . .  34
   2.1.46 Original-Recipient: header . . . . . . . . . . .  33
   2.1.56 Header field: Autoforwarded  . . . . .  34
   2.1.47 Content-Base: header . . . . . . . . . .  34
   2.1.57 Header field: Discarded-X400-IPMS-Extensions . . . . . . .  34
   2.1.58 Header field: Discarded-X400-MTS-Extensions  . .  35
   2.1.48 Content-Location: header . . . . .  35
   2.1.59 Header field: Disclose-Recipients  . . . . . . . . . . . .  35
   2.1.49 DL-Expansion-History:
   2.2    Permanent MIME header field registrations  . . . . . . . .  36
   2.2.1  Header field: MIME-Version . . . . . . .  36
   2.1.50 Alternate-Recipient: header  . . . . . . . . . . . .  36
   2.2.2  Header field: Content-ID . . .  36
   2.1.51 Original-Encoded-Information-Types: header . . . . . . . .  37
   2.1.52 Content-Return: header . . . . . .  37
   2.2.3  Header field: Content-Description  . . . . . . . . . . . .  37
   2.1.53 X400-Content-Return: header
   2.2.4  Header field: Content-Transfer-Encoding  . . . . . . . . .  38
   2.2.5  Header field: Content-Type . . . . . .  38
   2.1.54 Generate-Delivery-Report: header . . . . . . . . . .  38
   2.2.6  Header field: Content-Base . . . .  39
   2.1.55 Prevent-NonDelivery-Report: header . . . . . . . . . . . .  39
   2.1.56 Obsoletes: header
   2.2.7  Header field: Content-Location . . . . . . . . . . . . . .  39
   2.2.8  Header field: Content-features . . . . . .  40
   2.1.57 Content-Identifier: header . . . . . . . .  40
   2.2.9  Header field: Content-Disposition  . . . . . . . .  40
   2.1.58 Delivery-Date: header . . . .  40
   2.2.10 Header field: Content-Language . . . . . . . . . . . . . .  41
   2.1.59 Expiry-Date: header
   2.2.11 Header field: Content-Alternative  . . . . . . . . . . . .  41
   2.2.12 Header field: Content-MD5  . . . . . . .  41
   2.1.60 Reply-By: header . . . . . . . . . . . . . . . . . . . . .  42
   2.1.61 Importance: header .  42
   3.     IANA considerations  . . . . . . . . . . . . . . . . . . .  42
   2.1.62 Incomplete-Copy: header  . . . . . . . . . . . . . . . . .  43
   2.1.63 Priority: header . . . . . . . . . . . . . . . . . . . . .  44
   2.1.64 Sensitivity: header  . . . . . . . . . . . . . . . . . . .  44
   2.1.65 Language: header . . . . . . . . . . . . . . . . . . . . .  45
   2.1.66 Conversion: header . . . . . . . . . . . . . . . . . . . .  45
   2.1.67 Conversion-With-Loss: header
   4.     Security considerations  . . . . . . . . . . . . . . .  46
   2.1.68 Message-Type: header . .  42
   5.     Acknowledgements . . . . . . . . . . . . . . . . .  46
   2.1.69 Autoforwarded: header . . . .  42
          References . . . . . . . . . . . . . .  47
   2.1.70 Discarded-X400-IPMS-Extensions: header . . . . . . . . . .  48
   2.1.71 Discarded-X400-MTS-Extensions: header  43
          Authors' Addresses . . . . . . . . . .  48
   2.2    Provisional header registrations . . . . . . . . . .  44
   A.     Revision history . . .  49
   2.2.1  Message-Context: header . . . . . . . . . . . . . . . . .  51
   2.2.2  Apparently-To: header .  45
   A.1    draft-klyne-hdrreg-mail-02 . . . . . . . . . . . . . . . .  45
   A.2    draft-klyne-hdrreg-mail-01 .  51
   2.2.3  Approved-By: header . . . . . . . . . . . . . . .  45
   A.3    draft-klyne-hdrreg-mail-00 . . . .  52
   2.2.4  Fax: header . . . . . . . . . . . .  46
   B.     TODO:  . . . . . . . . . . .  53
   2.2.5  Telefax: header . . . . . . . . . . . . . . .  46
          Intellectual Property and Copyright Statements . . . . . .  53
   2.2.6  For-Approval:  47









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   2.2.7  For-Comment: registration         February 2004


1. Introduction

   This document defines IANA registration for a number of mail message
   and MIME header  . . . . . . . . . . . . . . . . . . .  54
   2.2.8  For-Handling: fields, per Registration procedures for message
   header . . . . . . . . . . . . . . . . . . .  55
   2.2.9  Mail-System-Version: header  . . . . . . . . . . . . . . .  55
   2.2.10 Mailer: header . . . . . . . . . . . . . . . . . . . . . .  56
   2.2.11 Originating-Client: header . . . . . . . . . . . . . . . .  56
   2.2.12 X-Mailer: header . . . . . . . . . . . . . . . . . . . . .  57
   2.2.13 X-Newsreader: header . . . . . . . . . . . . . . . . . . .  57
   2.2.14 X-MimeOLE: header  . . . . . . . . . . . . . . . . . . . .  58
   2.2.15 User-Agent: header . . . . . . . . . . . . . . . . . . . .  58
   2.2.16 Originator-Info: header  . . . . . . . . . . . . . . . . .  59
   2.2.17 Phone: header  . . . . . . . . . . . . . . . . . . . . . .  59



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   2.2.18 X-Envelope-From: header  . . . . . . . . . . . . . . . . .  60
   2.2.19 Envelope-To: header  . . . . . . . . . . . . . . . . . . .  60
   2.2.20 X-Envelope-To: header  . . . . . . . . . . . . . . . . . .  61
   2.2.21 X-Face: header . . . . . . . . . . . . . . . . . . . . . .  62
   2.2.22 X-RCPT-TO: header  . . . . . . . . . . . . . . . . . . . .  62
   2.2.23 X-Sender: header . . . . . . . . . . . . . . . . . . . . .  63
   2.2.24 X-X-Sender: header . . . . . . . . . . . . . . . . . . . .  63
   2.2.25 Posted-To: header  . . . . . . . . . . . . . . . . . . . .  64
   2.2.26 X-Admin: header  . . . . . . . . . . . . . . . . . . . . .  65
   2.2.27 Errors-To: header  . . . . . . . . . . . . . . . . . . . .  65
   2.2.28 Return-Receipt-To: header  . . . . . . . . . . . . . . . .  66
   2.2.29 Read-Receipt-To: header  . . . . . . . . . . . . . . . . .  66
   2.2.30 X-Confirm-reading-to: header . . . . . . . . . . . . . . .  67
   2.2.31 Return-Receipt-Requested: header . . . . . . . . . . . . .  68
   2.2.32 Register-Mail-Reply-Requested-By: header . . . . . . . . .  68
   2.2.33 Abuse-Reports-To: header . . . . . . . . . . . . . . . . .  69
   2.2.34 X-Complaints-To: header  . . . . . . . . . . . . . . . . .  69
   2.2.35 X-Report-Abuse-To: header  . . . . . . . . . . . . . . . .  70
   2.2.36 Content-Alias: header  . . . . . . . . . . . . . . . . . .  70
   2.2.37 Delivered-To: header . . . . . . . . . . . . . . . . . . .  71
   2.2.38 X-Loop: header . . . . . . . . . . . . . . . . . . . . . .  72
   2.2.39 Translated-By: header  . . . . . . . . . . . . . . . . . .  72
   2.2.40 Translation-Of: header . . . . . . . . . . . . . . . . . .  73
   2.2.41 X-UIDL: header . . . . . . . . . . . . . . . . . . . . . .  73
   2.2.42 X-URI: header  . . . . . . . . . . . . . . . . . . . . . .  74
   2.2.43 X-URL: header  . . . . . . . . . . . . . . . . . . . . . .  74
   2.2.44 X-IMAP: header . . . . . . . . . . . . . . . . . . . . . .  75
   2.2.45 X-OriginalArrivalTime: header  . . . . . . . . . . . . . .  75
   2.2.46 Precedence: header . . . . . . . . . . . . . . . . . . . .  76
   2.2.47 X-MSMail-Priority: header  . . . . . . . . . . . . . . . .  77
   2.2.48 X-Priority: header . . . . . . . . . . . . . . . . . . . .  77
   2.2.49 Content-Length: header . . . . . . . . . . . . . . . . . .  78
   2.2.50 Content-Conversion: header . . . . . . . . . . . . . . . .  78
   2.2.51 Content-Class: header  . . . . . . . . . . . . . . . . . .  79
   2.2.52 Content-SGML-Entity: header  . . . . . . . . . . . . . . .  79
   2.2.53 X-MIME-Autoconverted: header . . . . . . . . . . . . . . .  80
   2.2.54 List-Digest: header  . . . . . . . . . . . . . . . . . . .  80
   2.2.55 Mailing-List: header . . . . . . . . . . . . . . . . . . .  81
   2.2.56 X-Mailing-List: header . . . . . . . . . . . . . . . . . .  82
   2.2.57 List-Software: header  . . . . . . . . . . . . . . . . . .  82
   2.2.58 List-URL: header . . . . . . . . . . . . . . . . . . . . .  83
   2.2.59 X-Listserver: header . . . . . . . . . . . . . . . . . . .  83
   2.2.60 X-List-Host: header  . . . . . . . . . . . . . . . . . . .  84
   2.2.61 Fcc: header  . . . . . . . . . . . . . . . . . . . . . . .  84
   2.2.62 Speech-Act: header . . . . . . . . . . . . . . . . . . . .  85
   2.2.63 Status: header . . . . . . . . . . . . . . . . . . . . . .  85
   2.2.64 X-No-Archive: header . . . . . . . . . . . . . . . . . . .  86
   3.     IANA considerations  . . . . . . . . . . . . . . . . . . .  87



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   4.     Security considerations  . . . . . . . . . . . . . . . . .  87
   5.     Acknowledgements . . . . . . . . . . . . . . . . . . . . .  87
          References . . . . . . . . . . . . . . . . . . . . . . . .  87
          Author's Address . . . . . . . . . . . . . . . . . . . . .  89
   A.     Revision history . . . . . . . . . . . . . . . . . . . . .  89
   A.1    draft-klyne-hdrreg-mail-01 . . . . . . . . . . . . . . . .  89
   A.2    draft-klyne-hdrreg-mail-00 . . . . . . . . . . . . . . . .  89
   B.     TODO:  . . . . . . . . . . . . . . . . . . . . . . . . . .  90
          Full Copyright Statement . . . . . . . . . . . . . . . . .  91










































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1. Introduction

   This document defines IANA registration for a number of mail message
   header fields, per Registration procedures for message header fields
   [1].

   [[[The main body of this document is automatically generated.  Some
   sample HTML registry pages have been prepared from the same data, and
   can be found at [21].]]]

1.1 Structure of this document

   Section Section 2 contains the submission for initial registration of
   mail related message headers fields.

1.2 Document terminology and conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [10].

      NOTE: indented comments like this provide additional nonessential
      information about the rationale behind this document.

   [[[Editorial comments and questions about outstanding issues are
   provided in triple brackets like this.  These working comments should
   be resolved and removed prior to final publication.]]]

2. Registration templates

   Header registry entries are summarized in tabular form for
   convenience of reference, and presented in full in the following
   sections.

2.1 Permanent header registrations


   Header name         Protocol
   -----------         --------
   Date                mail      Message date and time
   From                mail      Mailbox of message author
   Sender              mail      Mailbox of message sender
   Reply-To            mail      Mailbox for replies to message
   To                  mail      Primary recipient mailbox
   Cc                  mail      Carbon-copy recipient mailbox
   Bcc                 mail      Blind-carbon-copy recipient
                                 mailbox
   Message-ID          mail      Message identifier



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   In-Reply-To         mail      Original message identifier(s)
   References          mail      Related message identifier(s)
   Subject             mail      Topic of message
   Comments            mail      Additional comments about the
                                 message
   Keywords            mail      Message key words and/or phrases
   Resent-Date         mail      Date and time message is resent
   Resent-From         mail      Mailbox of person for whom message
                                 is resent
   Resent-Sender       mail      Mailbox of person who actually
                                 resends the message
   Resent-To           mail      Mailbox to which message is resent
   Resent-Cc           mail      Mailbox(es) to which message is
                                 cc'ed on resend
   Resent-Bcc          mail      Mailbox(es) to which message is
                                 bcc'ed on resend
   Resent-Message-ID   mail      Message identifier for resent
                                 message
   Return-Path         mail      Message return path
   Received            mail      Mail transfer trace information
   Content-features    mail      Indicates content features of a
                                 MIME body part
   Content-Disposition mail      Intended content disposition and
                                 file name
   Disclose-Recipients mail      Disclose names of other
                                 recipients?
   Originator          mail      Similar to 'Sender:'
   PICS-Label          mail      PICS rating label
   Content-Language    mail      Language of message content
   Content-Alternative mail      Alternative content available
   Encoding            mail      Message encoding and other
                                 information
   Content-MD5         mail      MD5 checksum of content
   List-Archive        mail      URL of mailing list archive
   List-Help           mail      URL for mailing list information
   List-ID             mail      Mailing list identifier
   List-Owner          mail      URL for mailing list owner's
                                 mailbox
   List-Post           mail      URL for mailing list posting
   List-Subscribe      mail      URL for mailing list subscription
   List-Unsubscribe    mail      URL for mailing list
                                 unsubscription
   MIME-Version        mail      MIME version number
   Content-ID          mail      Identify content body part
   Content-Description mail      Description of message body part
   Content-Transfer-Encoding
                       mail      Content transfer encoding applied
   Content-Type        mail      MIME content type



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   Disposition-Notification-To
                       mail      Mailbox for sending disposition
                                 notification
   Disposition-Notification-Options
                       mail      Disposition notification options
   Original-Recipient  mail      MDN original recipient information
   Content-Base        mail      Base to be used for resolving
                                 relative URIs within this content
                                 part.
   Content-Location    mail      URI for retrieving a body part
   DL-Expansion-History
                       mail      Trace of distribution lists passed
   Alternate-Recipient mail      Controls forwarding to alternate
                                 recipients
   Original-Encoded-Information-Types
                       mail      Body part types in message
   Content-Return      mail      Return content on non-delivery?
   X400-Content-Return mail      Possible future name for
                                 'Content-Return:'
   Generate-Delivery-Report
                       mail      Request delivery report generation
   Prevent-NonDelivery-Report
                       mail      Non-delivery report required?
   Obsoletes           mail      Reference message to be replaced
   Content-Identifier  mail      Message content identifier
   Delivery-Date       mail      Message delivery time
   Expiry-Date         mail      Message expiry time
   Reply-By            mail      Time by which a reply is requested
   Importance          mail      Message importance
   Incomplete-Copy     mail      Body parts are missing.
   Priority            mail      Message priority
   Sensitivity         mail      Message content sensitivity
   Language            mail      X.400 message content lenguage
   Conversion          mail      Conversion allowed?
   Conversion-With-Loss
                       mail      Lossy conversion allowed?
   Message-Type        mail      Message type: delivery report?
   Autoforwarded       mail      Automatically forwarded indicator
   Discarded-X400-IPMS-Extensions
                       mail      X.400 IPM extensions discarded
   Discarded-X400-MTS-Extensions
                       mail      X.400 MTS extensions discarded


2.1.1 Date: header

   Header name:
      Date



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   Description:
      Message date and time

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.1)

   Related information:
      Specifies the date and time at which the creator of the message
      indicated that the message was complete and ready to enter the
      mail delivery system.


2.1.2 From: header

   Header name:
      From

   Description:
      Mailbox of message author

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)

   Related information:
      Specifies the author(s) of the message, that is, the mailbox(es)
      of the person(s) or system(s) responsible for the writing of the
      message.




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2.1.3 Sender: header

   Header name:
      Sender

   Description:
      Mailbox of message sender

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)

   Related information:
      Specifies the mailbox of the agent responsible for the actual
      transmission of the message.


2.1.4 Reply-To: header

   Header name:
      Reply-To

   Description:
      Mailbox for replies to message

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)

   Related information:



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      When the R"eply-To: "field is present, it indicates the
      mailbox(es) to which the author of the message suggests that
      replies be sent.


2.1.5 To: header

   Header name:
      To

   Description:
      Primary recipient mailbox

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)

   Related information:
      Contains the address(es) of the primary recipient(s) of the
      message.


2.1.6 Cc: header

   Header name:
      Cc

   Description:
      Carbon-copy recipient mailbox

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.



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   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)

   Related information:
      Bontains the addresses of others who are to receive the message,
      though the content of the message may not be directed at them.


2.1.7 Bcc: header

   Header name:
      Bcc

   Description:
      Blind-carbon-copy recipient mailbox

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)

   Related information:
      Contains addresses of recipients of the message whose addresses
      are not to be revealed to other recipients of the message.


2.1.8 Message-ID: header

   Header name:
      Message-ID

   Description:
      Message identifier

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track




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   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)

   Related information:
      Contains a single unique message identifier that refers to a
      particular version of a particular message.


2.1.9 In-Reply-To: header

   Header name:
      In-Reply-To

   Description:
      Original message identifier(s)

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)

   Related information:
      The message identifier(s) of the original message(s) to which the
      current message is a reply.


2.1.10 References: header

   Header name:
      References

   Description:
      Related message identifier(s)

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)



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   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)

   Related information:
      The message identifier(s) of other message(s) to which the current
      message may be related.


2.1.11 Subject: header

   Header name:
      Subject

   Description:
      Topic of message

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)

   Related information:
      Contains a short string identifying the topic of the message.


2.1.12 Comments: header

   Header name:
      Comments

   Description:
      Additional comments about the message




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   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)

   Related information:
      Contains any additional comments on the text of the body of the
      message.


2.1.13 Keywords: header

   Header name:
      Keywords

   Description:
      Message key words and/or phrases

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)

   Related information:
      Contains a comma-separated list of important words and phrases
      that might be useful for the recipient.


2.1.14 Resent-Date: header

   Header name:
      Resent-Date



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   Description:
      Date and time message is resent

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Contains the date and time that a message is reintroduced into the
      message transfer system.


2.1.15 Resent-From: header

   Header name:
      Resent-From

   Description:
      Mailbox of person for whom message is resent

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Contains the mailbox of the agent who has reintroduced the message
      into the message transfer system, or on whose behanlf the message
      has been resent.





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2.1.16 Resent-Sender: header

   Header name:
      Resent-Sender

   Description:
      Mailbox of person who actually resends the message

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Contains the mailbox of the agent who has reintroduced the message
      into the message transfer system, if this is different from the
      Resent-from value.


2.1.17 Resent-To: header

   Header name:
      Resent-To

   Description:
      Mailbox to which message is resent

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)




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   Related information:
      Contains the mailbox(es) to which the message has been resent.


2.1.18 Resent-Cc: header

   Header name:
      Resent-Cc

   Description:
      Mailbox(es) to which message is cc'ed on resend

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Containes the mailbox(es) to which message is cc'ed on resend


2.1.19 Resent-Bcc: header

   Header name:
      Resent-Bcc

   Description:
      Mailbox(es) to which message is bcc'ed on resend

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):



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      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Containes the mailbox(es) to which message is bcc'ed on resend


2.1.20 Resent-Message-ID: header

   Header name:
      Resent-Message-ID

   Description:
      Message identifier for resent message

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Contains a message identifier for a resent message


2.1.21 Return-Path: header

   Header name:
      Return-Path

   Description:
      Message return path

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.



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   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.7)

   Related information:
      Return path for message response diagnostics.  See also, RFC 2821.


2.1.22 Received: header

   Header name:
      Received

   Description:
      Mail transfer trace information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.7)

   Related information:
      Contains information about receipt of the current message by a
      mail transfer agent on the transfer path.  See also, RFC 2821.


2.1.23 Content-features: header

   Header name:
      Content-features

   Description:
      Indicates content features of a MIME body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:



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      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2912.txt (section 3)

   Related information:
      The 'Content-features:' header can be used to annotate a MIME body
      part with a media feature expression, to indicate features of the
      body part content.  See also: RFC 2533, RFC 2506, RFC 2045.


2.1.24 Content-Disposition: header

   Header name:
      Content-Disposition

   Description:
      Intended content disposition and file name

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      experimental

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2183.txt

   Related information:
      Whether a MIME body part is to be shown inline or is an
      attachment; can also indicate a suggested filename for use when
      saving an attachment to a file.


2.1.25 Disclose-Recipients: header

   Header name:
      Disclose-Recipients

   Description:
      Disclose names of other recipients?

   Applicable protocol:



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      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Tells whether recipients are to be told the names of other
      recipients of the same message.  This is primarily an X.400
      facility.  In X.400, this is an envelope attribute and refers to
      disclosure of the envelope recipient list.  Disclosure of other
      recipients is in Internet mail done via the To:, cc: and bcc:
      header fields.  Not for general use.


2.1.26 Originator: header

   Header name:
      Originator

   Description:
      Similar to 'Sender:'

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      experimental

   Author/change controller:
      Carl Malamud  (mailto:carl@malamud.com)
      Internet Multicasting Service.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1528.txt

   Related information:
      Sometimes used in Usenet News in similar ways to 'Sender:' Also
      used in printing protocols.  Non-standard in Usenet News,
      Experimental in RFC 1528 (tcp.int).





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2.1.27 PICS-Label: header

   Header name:
      PICS-Label

   Description:
      PICS rating label

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standard

   Author/change controller:
      W3C  (mailto:web-human@w3.org)
      World Wide Web Consortium.

   Specification document(s):
      http://www.w3.org/TR/REC-PICS-labels

   Related information:
      Ratings label to control selection (filtering) of messages
      according to the PICS protocol.  Specified for general use with
      RFC822 message format, with HTTP-specific extensions


2.1.28 Content-Language: header

   Header name:
      Content-Language

   Description:
      Language of message content

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1766.txt




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   Related information:
      Can include a code for the natural language used in a message,
      e.g.  'en' for English.


2.1.29 Content-Alternative: header

   Header name:
      Content-Alternative

   Description:
      Alternative content available

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      work-in-progress

   Author/change controller:
      Graham Klyne  (mailto:GK-headers@ninebynine.org)
      Clearswift Corporation,
      1310 Waterside,
      Arlington Business Park, Theale,
      Reading, RG7 4SA, UK.
      Tel: 011 8903 8903
      Fax: 011 8903 9000
      URL: http://www.mimesweeper.com/

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-ietf-fax-content-
      negotiation-05.txt

   Related information:
      Information about the media features of alternative content
      formats available for the current message.


2.1.30 Encoding: header

   Header name:
      Encoding

   Description:
      Message encoding and other information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)



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   Status:
      experimental

   Author/change controller:
      Albert K.  Costanzo  (mailto:AL@AKC.COM)
      AKC Consulting Inc..

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1505.txt

   Related information:
      Used in several different ways by different mail systems.  Some
      use it for a kind of content-type information, some for encoding
      and length information, some for a kind of boundary information,
      some in other ways.


2.1.31 Content-MD5: header

   Header name:
      Content-MD5

   Description:
      MD5 checksum of content

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1864.txt

   Related information:
      Checksum of content to ensure that it has not been modified.


2.1.32 List-Archive: header

   Header name:
      List-Archive

   Description:



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      URL of mailing list archive

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to browse the archives of the mailing list
      from which this message was relayed.


2.1.33 List-Help: header

   Header name:
      List-Help

   Description:
      URL for mailing list information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to get a information about the mailing list
      from which this message was relayed.







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2.1.34 List-ID: header

   Header name:
      List-ID

   Description:
      Mailing list identifier

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1919.txt

   Related information:
      Stores an identification of the mailing list, through which this
      message was distributed.


2.1.35 List-Owner: header

   Header name:
      List-Owner

   Description:
      URL for mailing list owner's mailbox

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:



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      Contains URL to send e-mail to the owner of the mailing list from
      which this message was relayed.


2.1.36 List-Post: header

   Header name:
      List-Post

   Description:
      URL for mailing list posting

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to send contributions to the mailing list from
      which this message was relayed.


2.1.37 List-Subscribe: header

   Header name:
      List-Subscribe

   Description:
      URL for mailing list subscription

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.




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   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to get a subscription to the mailing list from
      which this message was relayed.


2.1.38 List-Unsubscribe: header

   Header name:
      List-Unsubscribe

   Description:
      URL for mailing list unsubscription

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to unsubscribe the mailing list from which
      this message was relayed.


2.1.39 MIME-Version: header

   Header name:
      MIME-Version

   Description:
      MIME version number

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track




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   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 4)

   Related information:
      An indicator that this message is formatted according to the MIME
      standard, and an indication of which version of MIME is utilized.


2.1.40 Content-ID: header

   Header name:
      Content-ID

   Description:
      Identify content body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 7)

   Related information:
      Specifies a Unique ID for one MIME body part of the content of a
      message.


2.1.41 Content-Description: header

   Header name:
      Content-Description

   Description:
      Description of message body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)



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   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 8)

   Related information:
      Description of a particular body part of a message, for example a
      caption for an image body part.


2.1.42 Content-Transfer-Encoding: header

   Header name:
      Content-Transfer-Encoding

   Description:
      Content transfer encoding applied

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 6)

   Related information:
      Coding method used in a MIME message body part.


2.1.43 Content-Type: header

   Header name:
      Content-Type

   Description:
      MIME content type




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   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 5)

   Related information:
      Format of content (character set etc.) Note that the values for
      this header field are defined in different ways in RFC 1049 and in
      MIME (RFC 2045), look for the 'MIME-version' header field to
      understand if Content-Type is to be interpreted according to RFC
      1049 or according to MIME.  The MIME definition should be used in
      generating mail.  RFC 1049 has 'historic' status.  RFC 1766
      defines a parameter 'difference' to this header field.  Various
      other Content-Type define various additional parameters.  For
      example, the parameter 'charset' is mandatory for all textual
      Content-Types.  See also: RFC 1049,  RFC 1123: 5.2.13,  RFC 1766:
      4.1.


2.1.44 Disposition-Notification-To: header

   Header name:
      Disposition-Notification-To

   Description:
      Mailbox for sending disposition notification

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2298.txt




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   Related information:
      Indicates that the sender wants a disposition notification when
      this message is received (read, processed, etc.) by its
      recipients.


2.1.45 Disposition-Notification-Options: header

   Header name:
      Disposition-Notification-Options

   Description:
      Disposition notification options

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2298.txt

   Related information:
      For optional modifiers on disposition notification requests.


2.1.46 Original-Recipient: header

   Header name:
      Original-Recipient

   Description:
      MDN original recipient information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.



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   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2298.txt

   Related information:
      Original Recipient information for inclusion in disposition
      notifications.


2.1.47 Content-Base: header

   Header name:
      Content-Base

   Description:
      Base to be used for resolving relative URIs within this content
      part.

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2110.txt

   Related information:
      Base to be used for resolving relative URIs within this content
      part.


2.1.48 Content-Location: header

   Header name:
      Content-Location

   Description:
      URI for retrieving a body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track



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   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2110.txt

   Related information:
      URI with which the content of this content part might be
      retrievable.


2.1.49 DL-Expansion-History: header

   Header name:
      DL-Expansion-History

   Description:
      Trace of distribution lists passed

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Trace of distribution lists passed.  (MIXER X.400 mapping, not for
      general use.)


2.1.50 Alternate-Recipient: header

   Header name:
      Alternate-Recipient

   Description:
      Controls forwarding to alternate recipients

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)



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   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Controls whether this message may be forwarded to alternate
      recipients such as a postmaster if delivery is not possible to the
      intended recipient.  Default: Allowed.  RFC 2156 (MIXER), not for
      general usage.


2.1.51 Original-Encoded-Information-Types: header

   Header name:
      Original-Encoded-Information-Types

   Description:
      Body part types in message

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Which body part types occur in this message.  RFC 2156 (MIXER),
      not for general use.


2.1.52 Content-Return: header

   Header name:
      Content-Return




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   Description:
      Return content on non-delivery?

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Indicates whether the content of a message is to be returned with
      non-delivery notifications.  RFC 2156 (MIXER), not for general
      use.


2.1.53 X400-Content-Return: header

   Header name:
      X400-Content-Return

   Description:
      Possible future name for 'Content-Return:'

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Possible future change of name for 'Content-Return:'.







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2.1.54 Generate-Delivery-Report: header

   Header name:
      Generate-Delivery-Report

   Description:
      Request delivery report generation

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Indicates whether a delivery report fields [1].

   [[[The main body of this document is wanted automatically generated. Some
   sample HTML registry pages have been prepared from the same data, and
   can be found at successful
      delivery.  Default is not to generate such a report.  RFC 2156
      (MIXER), not  [21].]]]

1.1 Structure of this document

   Section Section 2 contains the submission for general usage.


2.1.55 Prevent-NonDelivery-Report: header

   Header name:
      Prevent-NonDelivery-Report

   Description:
      Non-delivery report required?

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt




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   Related information:
      Indicates whether non-delivery report is wanted on delivery error.
      Default is to generate such a report.  RFC 2156 (MIXER), not for
      general usage.


2.1.56 Obsoletes: header

   Header name:
      Obsoletes

   Description:
      Reference message to be replaced

   Applicable protocol: of
   mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Reference to a previous related message being corrected headers fields.

1.2 Document terminology and replaced.
      Compare to 'Supersedes:'.  This field may conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in the future this
   document are to be
      replaced with 'Supersedes:'.  RFC 2156, not for general use.


2.1.57 Content-Identifier: header

   Header name:
      Content-Identifier

   Description:
      Message content identifier

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:



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      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      A text string which identifies the content of a message. interpreted as described in RFC
      2156, not 2119 [10].

      NOTE: indented comments like this provide additional nonessential
      information about the rationale behind this document.

   [[[Editorial comments and questions about outstanding issues are
   provided in triple brackets like this.  These working comments should
   be resolved and removed prior to final publication.]]]

2. Registration templates

   Header registry entries are summarized in tabular form for general usage.


2.1.58 Delivery-Date:
   convenience of reference, and presented in full in the following
   sections.

2.1 Permanent mail header field registrations


   Header name:
      Delivery-Date

   Description: name         Protocol
   -----------         --------
   Date                Mail      Message delivery time

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      The date and time when a
   From                Mail      Mailbox of message was delivered to its recipient.  RFC 2156
      (MIXER), not author
   Sender              Mail      Mailbox of message sender
   Reply-To            Mail      Mailbox for general use.


2.1.59 Expiry-Date: header

   Header name:
      Expiry-Date

   Description: replies to message
   To                  Mail      Primary recipient mailbox
   Cc                  Mail      Carbon-copy recipient mailbox
   Bcc                 Mail      Blind-carbon-copy recipient
                                 mailbox
   Message-ID          Mail      Message expiry time

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt) identifier



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   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt         February 2004


   In-Reply-To         Mail      Original message identifier(s)
   References          Mail      Related information:
      Time at which a message loses its validity.  This field may in identifier(s)
   Subject             Mail      Topic of message
   Comments            Mail      Additional comments about the
      future be replaced by 'Expires:'.  RFC 2156 (MIXER), not for
      general use.


2.1.60 Reply-By: header

   Header name:
      Reply-By

   Description:
      Time by which a reply is requested

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Latest
                                 message
   Keywords            Mail      Message key words and/or phrases
   Resent-Date         Mail      Date and time at which a reply message is requested (not demanded).  RFC
      2156 (MIXER), not resent
   Resent-From         Mail      Mailbox of person for general usage.


2.1.61 Importance: header

   Header name:
      Importance

   Description:



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   Resent-Sender       Mail header registration               June 2002


      Message importance

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      A hint from      Mailbox of person who actually
                                 resends the originator message
   Resent-To           Mail      Mailbox to the recipients about how important a which message is.  Values: High, normal or low.  Not used is resent
   Resent-Cc           Mail      Mailbox(es) to control
      transmission speed.  Proposed which message is
                                 cc'ed on resend
   Resent-Bcc          Mail      Mailbox(es) to which message is
                                 bcc'ed on resend
   Resent-Message-ID   Mail      Message identifier for use with RFC 2156 (MIXER) resent
                                 message
   Return-Path         Mail      Message return path
   Received            Mail      Mail transfer trace information
   Disposition-Notification-To
                       Mail      Mailbox for sending disposition
                                 notification
   Disposition-Notification-Options
                       Mail      Disposition notification options
   Original-Recipient  Mail      MDN original recipient information
   Originator          Mail      Similar to 'Sender:'
   PICS-Label          Mail      PICS rating label
   Encoding            Mail      Message encoding and
      RFC 2421 (VPIM).


2.1.62 Incomplete-Copy: header

   Header name:
      Incomplete-Copy

   Description:
      Body parts are missing.

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information: other
                                 information
   List-Archive        Mail      URL of mailing list archive
   List-Help           Mail      URL for mailing list information
   List-ID             Mail      Mailing list identifier
   List-Owner          Mail      URL for mailing list owner's
                                 mailbox
   List-Post           Mail      URL for mailing list posting
   List-Subscribe      Mail      URL for mailing list subscription
   List-Unsubscribe    Mail      URL for mailing list
                                 unsubscription
   Message-Context     Mail      Type or context of message
   DL-Expansion-History
                       Mail      Trace of distribution lists passed
   Alternate-Recipient Mail      Controls forwarding to alternate
                                 recipients
   Original-Encoded-Information-Types
                       Mail      Body parts are missing.  RFC 2156 (MIXER), not for general usage. part types in message
   Content-Return      Mail      Return content on non-delivery?
   Generate-Delivery-Report



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2.1.63 Priority: header

   Header name:         February 2004


                       Mail      Request delivery report generation
   Prevent-NonDelivery-Report
                       Mail      Non-delivery report required?
   Obsoletes           Mail      Reference message to be replaced
   Content-Identifier  Mail      Message content identifier
   Delivery-Date       Mail      Message delivery time
   Expiry-Date         Mail      Message expiry time
   Reply-By            Mail      Time by which a reply is requested
   Importance          Mail      Message importance
   Incomplete-Copy     Mail      Body parts are missing.
   Priority

   Description:            Mail      Message priority

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Can be 'normal', 'urgent' or 'non-urgent' and can influence
      transmission speed and delivery.  RFC 2156 (MIXER), not for
      general use.


2.1.64 Sensitivity: header

   Header name:
   Sensitivity

   Description:         Mail      Message content sensitivity

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt




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   Language            Mail header registration               June 2002


   Related information:
      How sensitive it is to disclose this message to other people than
      the specified recipients.  Values: Personal, private, company
      confidential.  The absence of this header field in messages
      gatewayed from      X.400 indicates that the message is not sensitive.
      Proposed for use with RFC 2156 (MIXER) and RFC 2421 (VPIM).


2.1.65 Language: header content lenguage
   Conversion          Mail      Conversion allowed?
   Conversion-With-Loss
                       Mail      Lossy conversion allowed?
   Message-Type        Mail      Message type: delivery report?
   Autoforwarded       Mail      Automatically forwarded indicator
   Discarded-X400-IPMS-Extensions
                       Mail      X.400 IPM extensions discarded
   Discarded-X400-MTS-Extensions
                       Mail      X.400 MTS extensions discarded
   Disclose-Recipients Mail      Disclose names of other
                                 recipients?

                                Figure 1


2.1.1 Header name:
      Language field: Date

   Description:
      X.400 message content lenguage
      Message date and time

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Can include a code for the natural language used in a message,
      e.g.  'en' for English.  RFC 2156 (MIXER), not for general usage.


2.1.66 Conversion: header

   Header name:
      Conversion

   Description:
      Conversion allowed?

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track (section 3.6.1)






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   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt         February 2004


   Related information:
      The body
      Specifies the date and time at which the creator of this the message may not be converted from one character
      set to another.  Values: Prohibited
      indicated that the message was complete and allowed.  RFC 2156
      (MIXER), not for general use.


2.1.67 Conversion-With-Loss: header ready to enter the
      mail delivery system.


2.1.2 Header name:
      Conversion-With-Loss field: From

   Description:
      Lossy conversion allowed?

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      The body
      Mailbox of this message may not be converted from one character
      set to another if information will be lost.  Values: Prohibited
      and allowed.  RFC 2156 (MIXER), not for general use.


2.1.68 Message-Type: header

   Header name:
      Message-Type

   Description:
      Message type: delivery report?




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   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)

   Related information:
      Only used with
      Specifies the value 'Delivery Report' to indicates author(s) of the message, that this
      is a delivery report gatewayed from X.400.  RFC 2156 (MIXER), not is, the mailbox(es)
      of the person(s) or system(s) responsible for general use.


2.1.69 Autoforwarded: header the writing of the
      message.


2.1.3 Header name:
      Autoforwarded field: Sender

   Description:
      Automatically forwarded indicator
      Mailbox of message sender

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt

   Related information:
      Has been automatically forwarded.  RFC 2156 (MIXER), not for
      general usage.
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)




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2.1.70 Discarded-X400-IPMS-Extensions: header         February 2004


   Related information:
      Specifies the mailbox of the agent responsible for the actual
      transmission of the message.


2.1.4 Header name:
      Discarded-X400-IPMS-Extensions field: Reply-To

   Description:
      X.400 IPM extensions discarded
      Mailbox for replies to message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.2)

   Related information:
      Can be used in Internet mail
      When the "Reply-To:" field is present, it indicates the
      mailbox(es) to indicate X.400 IPM extensions which could not the author of the message suggests that
      replies be mapped to Internet mail format.  RFC 2156
      (MIXER), not for general usage.


2.1.71 Discarded-X400-MTS-Extensions: header sent.


2.1.5 Header name:
      Discarded-X400-MTS-Extensions field: To

   Description:
      X.400 MTS extensions discarded
      Primary recipient mailbox

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)





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   Related information:
      Can be used in Internet mail to indicate X.400 MTS extensions
      which could not be mapped to Internet mail format.  RFC 2156
      (MIXER), not for general usage.


2.2 Provisional header registrations


   Header name         Protocol
   -----------         --------
   Message-Context     mail      Type or context of message
   Apparently-To       mail      Envelope recipients inserted my
                                 MTA
   Approved-By         mail      Mailing list moderator who has
                                 approved message
   Fax                 mail      Fax number of
      Contains the originator
   Telefax             mail      Fax number address(es) of the originator
   For-Approval        mail      Recipients for approval of this
                                 message
   For-Comment         mail      Recipients for comment on this
                                 message
   For-Handling        mail      Primary recipients for handling
                                 this message
   Mail-System-Version mail      Information about originating
                                 client software
   Mailer              mail      Information about originating
                                 client software
   Originating-Client  mail      Information about originating
                                 client software
   X-Mailer            mail      Information about originating
                                 client software
   X-Newsreader        mail      Information about originating
                                 client software
   X-MimeOLE           mail      Information about originating
                                 client software
   User-Agent          mail      Information about originating
                                 client software
   Originator-Info     mail      Originator authentication
                                 information
   Phone               mail      Phone number primary recipient(s) of the originator.
   X-Envelope-From     mail      Mail envelope sender
   Envelope-To         mail      Mail envelope
      message.


2.1.6 Header field: Cc

   Description:
      Carbon-copy recipient
   X-Envelope-To       mail mailbox

   Applicable protocol:
      Mail envelope recipient
   X-Face              mail      Picture (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)

   Related information:
      Contains the addresses of others who are to receive the message,
      though the content of the sender
   X-RCPT-TO           mail      Mail envelope recipient
   X-Sender            mail      Tentative message sender
   X-X-Sender          mail      Extra-tentative message sender may not be directed at them.


2.1.7 Header field: Bcc

   Description:
      Blind-carbon-copy recipient mailbox

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.3)






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   Posted-To           mail      Nesgroup to which         February 2004


   Related information:
      Contains addresses of recipients of the message was sent
   X-Admin             mail      Submission server administrator
                                 mailbox
   Errors-To           mail      Address for notifications to be
                                 sent
   Return-Receipt-To   mail      Address for notifications to be
                                 sent
   Read-Receipt-To     mail      Address for notifications to be
                                 sent
   X-Confirm-reading-to
                       mail      Address for notifications to be
                                 sent
   Return-Receipt-Requested
                       mail      Address for notifications to be
                                 sent
   Register-Mail-Reply-Requested-By
                       mail      Address for notifications whose addresses
      are not to be
                                 sent
   Abuse-Reports-To    mail      Mailbox for reporting abuse
   X-Complaints-To     mail      Mailbox for reporting abuse
   X-Report-Abuse-To   mail      Mailbox for reporting abuse
   Content-Alias       mail      Alternatice revealed to Content-Location
                                 URI
   Delivered-To        mail      Message loop detection
   X-Loop              mail      Message loop detection
   Translated-By       mail      Mailbox of translator
   Translation-Of      mail      Reference source other recipients of translation
   X-UIDL              mail the message.


2.1.8 Header field: Message-ID

   Description:
      Message identifier within
                                 mailstore
   X-URI               mail      URI of body part content
   X-URL               mail      Location of body part content
   X-IMAP              mail      IMAP UID
   X-OriginalArrivalTime
                       mail      Time message was submitted
   Precedence          mail      Message precedence indicator
   X-MSMail-Priority   mail      Yet another priority indication.
   X-Priority          mail      Message priority
   Content-Length      mail      Size in bytes of body part
   Content-Conversion  mail      Variant of 'Conversion:'
   Content-Class       mail      Hierarchical content
                                 classification
   Content-SGML-Entity mail      SGML entity information
   X-MIME-Autoconverted
                       mail      In-transit message conversion
                                 information
   List-Digest         mail      URL for mailing list digest
                                 subscription
   Mailing-List        mail      Mailing list information



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   Applicable protocol:
      Mail header registration               June 2002


   X-Mailing-List      mail      Mailing list information
   List-Software       mail      Mailing list software information
   List-URL            mail      URL for mailing list information
   X-Listserver        mail      List server software information
   X-List-Host         mail      List server software information
   Fcc                 mail      File for copy of (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)

   Related information:
      Contains a single unique message
   Speech-Act          mail      Speech act categorization identifier that refers to a
      particular version of a particular message. If the message
   Status              mail      Message status in delivery system
   X-No-Archive        mail      Do not archive publicly


2.2.1 Message-Context: header is
      resent without changes, the original Message-ID is retained.


2.1.9 Header name:
      Message-Context field: In-Reply-To

   Description:
      Type or context of
      Original message identifier(s)

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Can have the values 'voice-message', 'fax-message', 'pager-
      message', 'multimedia-message', 'text-message', 'none'


2.2.2 Apparently-To: header

   Header name:
      Apparently-To

   Description:
      Envelope recipients inserted my MTA

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)





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   Status:
      Non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt         February 2004


   Related information:
      Inserted by Sendmail when there is no 'To:' recipient in
      The message identifier(s) of the original message, listing recipients derived from the envelope
      into message(s) to which the
      current message heading.  This behavior is not quite proper, MTAs
      should not modify headings (except inserting Received lines), and
      it can in some cases cause Bcc recipients to be wrongly divulged
      to non-Bcc recipients.  Discouraged, mentioned in RFC 1211.


2.2.3 Approved-By: header a reply.


2.1.10 Header name:
      Approved-By field: References

   Description:
      Mailing list moderator who has approved
      Related message identifier(s)

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.4)

   Related information:
      Name of the moderator of a mailing list, who has approved this
      The message for distribution identifier(s) of other message(s) to which the members of current
      message may be related. In RFC2822, the list.  Non-
      standard, used by some mailing list expansion systems.







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2.2.4 Fax: definition was changed to
      say that this header

   Header name:
      Fax

   Description:
      Fax number field contains a list of the originator

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Fax number all Message-IDs of
      messages in the originator.


2.2.5 Telefax: header preceding reply chain.


2.1.11 Header name:
      Telefax field: Subject

   Description:
      Fax number
      Topic of the originator message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Fax number of the originator.
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)




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2.2.6 For-Approval: header         February 2004


   Related information:
      Contains a short string identifying the topic of the message.


2.1.12 Header name:
      For-Approval field: Comments

   Description:
      Recipients for approval of this
      Additional comments about the message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)

   Related information:
      Primary recipients, who are requested to approve
      Contains any additional comments on the information
      in text of the body of the
      message. Warning: Some mailers will not show this message or its attachments.


2.2.7 For-Comment: header field to
      recipients.


2.1.13 Header name:
      For-Comment field: Keywords

   Description:
      Recipients for comment on this message
      Message key words and/or phrases

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.5)






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      Primary recipients, who are requested to comment on         February 2004


   Related information:
      Contains a comma-separated list of important words and phrases
      that might be useful for the
      information in this message or its attachments.


2.2.8 For-Handling: header recipient.


2.1.14 Header name:
      For-Handling field: Resent-Date

   Description:
      Primary recipients for handling this
      Date and time message is resent

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Primary recipients, who are requested to handle
      Contains the information in
      this date and time that a message or its attachments.


2.2.9 Mail-System-Version: header is reintroduced into the
      message transfer system.


2.1.15 Header name:
      Mail-System-Version field: Resent-From

   Description:
      Information about originating client software
      Mailbox of person for whom message is resent

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)






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      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt         February 2004


   Related information:
      Information about
      Contains the client software mailbox of the originator.


2.2.10 Mailer: header agent who has reintroduced the message
      into the message transfer system, or on whose behanlf the message
      has been resent.


2.1.16 Header name:
      Mailer field: Resent-Sender

   Description:
      Information about originating client software
      Mailbox of person who actually resends the message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Information about
      Contains the client software mailbox of the originator.


2.2.11 Originating-Client: header agent who has reintroduced the message
      into the message transfer system, if this is different from the
      Resent-from value.


2.1.17 Header name:
      Originating-Client field: Resent-To

   Description:
      Information about originating client software
      Mailbox to which message is resent

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)




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   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt         February 2004


   Related information:
      Information about
      Contains the client software of mailbox(es) to which the originator.


2.2.12 X-Mailer: header message has been resent.


2.1.18 Header name:
      X-Mailer field: Resent-Cc

   Description:
      Information about originating client software
      Mailbox(es) to which message is cc'ed on resend

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Information about the client software of
      Containes the originator.


2.2.13 X-Newsreader: header mailbox(es) to which message is cc'ed on resend


2.1.19 Header name:
      X-Newsreader field: Resent-Bcc

   Description:
      Information about originating client software
      Mailbox(es) to which message is bcc'ed on resend

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:



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      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Information about the client software of
      Containes the originator.


2.2.14 X-MimeOLE: mailbox(es) to which message is bcc'ed on resend





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2.1.20 Header name:
      X-MimeOLE field: Resent-Message-ID

   Description:
      Information about originating client software
      Message identifier for resent message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.6)

   Related information:
      Information about the client software of the originator.


2.2.15 User-Agent: header
      Contains a message identifier for a resent message


2.1.21 Header name:
      User-Agent field: Return-Path

   Description:
      Information about originating client software
      Message return path

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.7)

   Related information:
      Return path for message response diagnostics. See also, RFC 2821.


2.1.22 Header field: Received






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   Description:
      Mail transfer trace information

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2822.txt (section 3.6.7)

   Related information:
      Information
      Contains information about the client software receipt of the originator.


2.2.16 Originator-Info: header current message by a
      mail transfer agent on the transfer path. See also, RFC 2821.


2.1.23 Header name:
      Originator-Info field: Disposition-Notification-To

   Description:
      Originator authentication information
      Mailbox for sending disposition notification

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-newman-msgheader-
      originfo-05.txt

   Related information:
      Contains information about the authentication of
      http://www.rfc-editor.org/rfc/rfc2298.txt

   Related information:
      Indicates that the originator in sender wants a format which disposition notification when
      this message is not easily used to send email to, to avoid the
      problems with 'Sender' and 'X-Sender'.


2.2.17 Phone: header received (read, processed, etc.) by its
      recipients.


2.1.24 Header name:
      Phone

   Description:
      Phone number of the originator.

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt) field: Disposition-Notification-Options





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   Description:
      Disposition notification options

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2298.txt

   Related information:
      Phone number of the originator.


2.2.18 X-Envelope-From: header
      For optional modifiers on disposition notification requests.


2.1.25 Header name:
      X-Envelope-From field: Original-Recipient

   Description:
      Mail envelope sender
      MDN original recipient information

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2298.txt

   Related information:
      If the sender in the envelope (SMTP 'MAIL FROM') is not the same
      as the senders
      Original Recipient information for inclusion in the 'From' or 'Sender' header fields, some mail
      servers add this as an aid to clients which would otherwise not be
      able to display this information.


2.2.19 Envelope-To: header disposition
      notifications.


2.1.26 Header name:
      Envelope-To field: Originator

   Description:
      Similar to 'Sender:'




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      Mail envelope recipient         February 2004


   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      experimental

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      Carl Malamud  (mailto:carl@malamud.com)
      Internet Multicasting Service.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc1528.txt

   Related information:
      If the recipient
      Sometimes used in the envelope (SMTP 'RCPT TO') is not included Usenet News in the CC list, some mail servers add this header field as an aid
      to clients which would otherwise not be able similar ways to display the
      envelope recipients.


2.2.20 X-Envelope-To: header 'Sender:' Also
      used in printing protocols. Non-standard in Usenet News,
      Experimental in RFC 1528 (tcp.int).


2.1.27 Header name:
      X-Envelope-To field: PICS-Label

   Description:
      Mail envelope recipient
      PICS rating label

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      W3C  (mailto:web-human@w3.org)
      World Wide Web Consortium.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.w3.org/TR/REC-PICS-labels

   Related information:
      If the recipient in the envelope (SMTP 'RCPT TO') is not included
      in the CC list, some mail servers add this header field as an aid
      Ratings label to clients which would otherwise not be able control selection (filtering) of messages
      according to display the
      envelope recipients. PICS protocol.  Specified for general use with
      RFC822 message format, with HTTP-specific extensions


2.1.28 Header field: Encoding

   Description:
      Message encoding and other information




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2.2.21 X-Face: header

   Header name:
      X-Face

   Description:
      Picture of the sender         February 2004


   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      experimental

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      Albert K. Costanzo  (mailto:AL@AKC.COM)
      AKC Consulting Inc..

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc1505.txt

   Related information:
      48x48 bitmap with picture
      Used in several different ways by different mail systems. Some use
      it for a kind of the sender content-type information, some for encoding and
      length information, some for a kind of this message.


2.2.22 X-RCPT-TO: header boundary information, some
      in other ways.


2.1.29 Header name:
      X-RCPT-TO field: List-Archive

   Description:
      Mail envelope recipient
      URL of mailing list archive

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Mail header field indication of
      Contains URL to use to browse the archives of the SMTP envelope recipient mailing list
      from which this message was relayed.


2.1.30 Header field: List-Help

   Description:
      URL for mailing list information




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      for this message.


2.2.23 X-Sender: header

   Header name:
      X-Sender

   Description:
      Tentative message sender         February 2004


   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Some mail software expect 'Sender:' to be an e-mail address which
      you can send mail to.  However, some mail software has as the best
      authenticated sender a POP or IMAP account, which you might not be
      able to send to.  Because of this, some mail software put the POP
      or IMAP account into an X-sender header field instead of a Sender
      header field, to indicate that you may not be able to send e-mail
      Contains URL to this address.  See also 'X-X-Sender'.  Another use of 'X-
      Sender:' is that some e-mail software, which wants to insert get a
      'Sender:' header, will first change an existing 'Sender:' header
      to 'X-Sender'.  This use is actually often the same as that
      described above, since information about the new 'Sender:' is added because it is
      better authenticated than mailing list
      from which this message was relayed.


2.1.31 Header field: List-ID

   Description:
      Mailing list identifier

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc1919.txt

   Related information:
      Stores an identification of the old value.


2.2.24 X-X-Sender: header mailing list, through which this
      message was distributed.


2.1.32 Header name:
      X-X-Sender field: List-Owner

   Description:
      Extra-tentative message sender

   Applicable protocol:
      URL for mailing list owner's mailbox






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      mail         February 2004


   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Even though some systems put the POP or IMAP account name into the
      'X-Sender:' instead of the Sender header field, some mail software
      tries
      Contains URL to send e-mail to the 'X-Sender:' too.  To stop this, some systems
      have begun to use 'X-X-Sender:' to indicate an authentication owner of the sender which might not be useable to send e-mail to.  See also
      'Originator-Info:'.


2.2.25 Posted-To: header

   Header name:
      Posted-To

   Description:
      Nesgroup to mailing list from
      which this message was sent relayed.


2.1.33 Header field: List-Post

   Description:
      URL for mailing list posting

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      When a message is sent both
      Contains URL to netnews and e-mail, this header is
      used in the e-mail version of the message use to indicate send contributions to the mailing list from
      which
      newsgroup it this message was sent to.  This header thus contains the same
      information as the 'Newsgroups:' header in the netnews version of
      the message. relayed.


2.1.34 Header field: List-Subscribe

   Description:
      URL for mailing list subscription






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2.2.26 X-Admin: header         February 2004


   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      Contains URL to use to get a subscription to the mailing list from
      which this message was relayed.


2.1.35 Header name:
      X-Admin field: List-Unsubscribe

   Description:
      Submission server administrator mailbox
      URL for mailing list unsubscription

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2369.txt

   Related information:
      E-mail address of administrator of a server, through
      Contains URL to use to unsubscribe the mailing list from which
      this message was submitted.


2.2.27 Errors-To: was relayed.


2.1.36 Header field: Message-Context

   Description:
      Type or context of message






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   Header name:
      Errors-To

   Description:
      Address for notifications to be sent registration         February 2004


   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      Standards track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc3458.txt

   Related information:



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      Address to which notifications are to be sent
      Provides information about the context and presentation
      characteristics of a request to get
      delivery notifications.  Internet standards recommend, however, message.  Can have the use of MAIL FROM and Return-Path, not Errors-To, for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used.


2.2.28 Return-Receipt-To: header values
      'voice-message', 'fax-message', 'pager-message',
      'multimedia-message', 'text-message', 'none'.


2.1.37 Header name:
      Return-Receipt-To field: DL-Expansion-History

   Description:
      Address for notifications to be sent
      Trace of distribution lists passed

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Address to which notifications are to be sent and a request to get
      delivery notifications.  Internet standards recommend, however,
      the use
      Trace of MAIL FROM and Return-Path, distribution lists passed. (MIXER X.400 mapping, not Errors-To, for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used.


2.2.29 Read-Receipt-To: header
      general use.)


2.1.38 Header name:
      Read-Receipt-To field: Alternate-Recipient

   Description:
      Address for notifications
      Controls forwarding to be sent

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status: alternate recipients




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      non-standard         February 2004


   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Address to which notifications are to
      Controls whether this message may be sent and a request forwarded to get alternate
      recipients such as a postmaster if delivery notifications.  Internet standards recommend, however, is not possible to the use of MAIL FROM and Return-Path,
      intended recipient. Default: Allowed. RFC 2156 (MIXER), not Errors-To, for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used.


2.2.30 X-Confirm-reading-to: header
      general usage.


2.1.39 Header name:
      X-Confirm-reading-to field: Original-Encoded-Information-Types

   Description:
      Address for notifications to be sent
      Body part types in message

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Address to which notifications are to be sent and a request to get
      delivery notifications.  Internet standards recommend, however,
      the use of MAIL FROM and Return-Path,
      Which body part types occur in this message. RFC 2156 (MIXER), not Errors-To,
      for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used. general use.


2.1.40 Header field: Content-Return

   Description:
      Return content on non-delivery?




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2.2.31 Return-Receipt-Requested: header

   Header name:
      Return-Receipt-Requested

   Description:
      Address for notifications to be sent         February 2004


   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Address to which notifications are to be sent and
      Indicates whether the content of a request message is to get
      delivery be returned with
      non-delivery notifications.  Internet standards recommend, however,
      the use of MAIL FROM and Return-Path, RFC 2156 (MIXER), not Errors-To, for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used.


2.2.32 Register-Mail-Reply-Requested-By: header general use.


2.1.41 Header name:
      Register-Mail-Reply-Requested-By field: Generate-Delivery-Report

   Description:
      Address for notifications to be sent
      Request delivery report generation

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Indicates whether a delivery report is wanted at successful
      delivery. Default is not to generate such a report. RFC 2156
      (MIXER), not for general usage.


2.1.42 Header field: Prevent-NonDelivery-Report

   Description:
      Non-delivery report required?





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      06.txt         February 2004


   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Address to which notifications are
      Indicates whether non-delivery report is wanted on delivery error.
      Default is to be sent and generate such a request to get
      delivery notifications.  Internet standards recommend, however,
      the use of MAIL FROM and Return-Path, report. RFC 2156 (MIXER), not Errors-To, for where
      delivery notifications are to be sent.  Non-standard, discouraged,
      may be widely used.


2.2.33 Abuse-Reports-To: header
      general usage.


2.1.43 Header name:
      Abuse-Reports-To field: Obsoletes

   Description:
      Mailbox for reporting abuse
      Reference message to be replaced

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Indicates where
      Reference to send complaints if you get a previous message which you
      think is against being corrected and replaced.
      Compare to 'Supersedes:' used in Usenet News. This field may in
      the laws or rules.


2.2.34 X-Complaints-To: header

   Header name:
      X-Complaints-To

   Description:
      Mailbox future be replaced with a different name. RFC 2156 (MIXER),
      not for reporting abuse

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status: general usage.


2.1.44 Header field: Content-Identifier






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      non-standard         February 2004


   Description:
      Message content identifier

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Indicates where to send complaints if you get a message
      A text string which you
      think is against identifies the laws or rules.


2.2.35 X-Report-Abuse-To: header content of a message. RFC 2156
      (MIXER), not for general usage.


2.1.45 Header name:
      X-Report-Abuse-To field: Delivery-Date

   Description:
      Mailbox for reporting abuse
      Message delivery time

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Indicates where to send complaints if you get
      The time when a message which you
      think is against the laws or rules.


2.2.36 Content-Alias: header

   Header name:
      Content-Alias

   Description:
      Alternatice was delivered to Content-Location URI its recipient. RFC 2156
      (MIXER), not for general use.


2.1.46 Header field: Expiry-Date






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   Description:
      Message expiry time

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Used in addition to Content-Location if this content part can be
      retrieved through more than one URI.  Only one of them is allowed
      Time at which a message loses its validity. This field may in the Content-Location, the other can
      future be specified in Content-
      Alias.


2.2.37 Delivered-To: header replaced by 'Expires:'. RFC 2156 (MIXER), not for
      general use.


2.1.47 Header name:
      Delivered-To field: Reply-By

   Description:
      Message loop detection
      Time by which a reply is requested

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Used by some automatic services (mainly MLMs and autoresponders)
      for the purpose of loop detection.  The service adds the
      Delivered-To header to outgoing messages, with its e-mail address
      as a value, and discards incoming messages
      Latest time at which already have it. a reply is requested (not demanded). RFC 2156
      (MIXER), not for general usage.


2.1.48 Header field: Importance





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2.2.38 X-Loop: header

   Header name:
      X-Loop         February 2004


   Description:
      Message loop detection importance

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Used by some automatic services (mainly MLMs and autoresponders)
      for the purpose of loop detection.  The service adds
      A hint from the
      Delivered-To header originator to outgoing messages, with its e-mail address
      as the recipients about how important a value,
      message is.  Values: High, normal or low. Not used to control
      transmission speed. Proposed for use with RFC 2156 (MIXER) and discards incoming messages which already have it.


2.2.39 Translated-By: header RFC
      2421 (VPIM).


2.1.49 Header name:
      Translated-By field: Incomplete-Copy

   Description:
      Mailbox of translator
      Body parts are missing.

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Body parts are missing. RFC 2156 (MIXER), not for general usage.


2.1.50 Header field: Priority





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   Related information:
      Mailbox of the person who made the translation.


2.2.40 Translation-Of: header

   Header name:
      Translation-Of         February 2004


   Description:
      Reference source of translation
      Message priority

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Reference to the Message-ID of a message, of which the current
      message is a translation.


2.2.41 X-UIDL: header
      Can be 'normal', 'urgent' or 'non-urgent' and can influence
      transmission speed and delivery. RFC 2156 (MIXER), not for general
      use.


2.1.51 Header name:
      X-UIDL field: Sensitivity

   Description:
      Message identifier within mailstore content sensitivity

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):



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      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Unique identifier for a message, local
      How sensitive it is to a particular local
      mailbox store. disclose this message to other people than
      the specified recipients. Values: Personal, private, company
      confidential. The UIDL identifier is defined absence of this header field in messages
      gatewayed from X.400 indicates that the POP3
      standard, but not the 'X-UIDL:' header.


2.2.42 X-URI: header

   Header name:
      X-URI

   Description:
      URI of body part content

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Similar usage as 'X-URL', but may indicate any URI, message is not just a
      URL.


2.2.43 X-URL: sensitive.
      Proposed for use with RFC 2156 (MIXER) and RFC 2421 (VPIM).





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2.1.52 Header name:
      X-URL field: Language

   Description:
      Location of body part
      X.400 message content lenguage

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard



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      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Sometimes used with the same meaning as 'Content-Location:',
      sometimes to indicate the web home page of
      Can include a code for the sender or of his
      organisation.


2.2.44 X-IMAP: header natural language used in a message,
      e.g. 'en' for English. See also 'Content-Language'. RFC 2156
      (MIXER), not for general usage.


2.1.53 Header name:
      X-IMAP field: Conversion

   Description:
      IMAP UID
      Conversion allowed?

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      The UID, as defined in the IMAP standard.  Only used in internal
      mailbox storage in some mail systems, should never body of this message may not be visible converted from one character
      set to a
      user.


2.2.45 X-OriginalArrivalTime: header

   Header name:
      X-OriginalArrivalTime

   Description:
      Time message was submitted another.  Values: Prohibited and allowed. RFC 2156 (MIXER),
      not for general use.





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2.1.54 Header field: Conversion-With-Loss

   Description:
      Lossy conversion allowed?

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Time when
      The body of this message was delivered into the message transport
      system (usually the same time as in the last 'Received:' header)


2.2.46 Precedence: header may not be converted from one character
      set to another if information will be lost. Values: Prohibited and
      allowed. RFC 2156 (MIXER), not for general use.


2.1.55 Header name:
      Precedence field: Message-Type

   Description:
      Message precedence indicator type: delivery report?

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Sometimes
      Only used as a priority with the value which can influence
      transmission speed and delivery.  Common values are 'bulk' and
      'first-class'.  Other uses is to control automatic replies and to
      control return-of-content facilities, and 'Delivery Report' to stop mailing list
      loops.  Non-standard, controversial, widely used. indicates that this
      is a delivery report gatewayed from X.400. RFC 2156 (MIXER), not
      for general use.





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2.2.47 X-MSMail-Priority: header         February 2004


2.1.56 Header name:
      X-MSMail-Priority field: Autoforwarded

   Description:
      Yet another priority indication.
      Automatically forwarded indicator

   Applicable protocol:
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Has been automatically forwarded. RFC 2156 (MIXER), not for
      general usage.


2.1.57 Header field: Discarded-X400-IPMS-Extensions

   Description:
      X.400 IPM extensions discarded

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Yet another priority indication.


2.2.48 X-Priority:
      Can be used in Internet mail to indicate X.400 IPM extensions
      which could not be mapped to Internet mail format. RFC 2156
      (MIXER), not for general usage.






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2.1.58 Header name:
      X-Priority field: Discarded-X400-MTS-Extensions

   Description:
      Message priority
      X.400 MTS extensions discarded

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Values: 1 (Highest), 2 (High), 3 (Normal), 4 (Low), 5 (Lowest).  3



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      (Normal) is default if the field is omitted.  See also the Eudora
      Pro Macintosh User Manual, QUALCOMM Inc


2.2.49 Content-Length: header
      Can be used in Internet mail to indicate X.400 MTS extensions
      which could not be mapped to Internet mail format. RFC 2156
      (MIXER), not for general usage.


2.1.59 Header name:
      Content-Length field: Disclose-Recipients

   Description:
      Size in bytes
      Disclose names of body part other recipients?

   Applicable protocol:
      mail
      Mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2156.txt

   Related information:
      Inserted by certain mailers
      Tells whether recipients are to indicate be told the size in bytes names of other
      recipients of the
      message text. same message.  This is part of a format some mailers use when
      showing a message primarily an X.400
      facility.  In X.400, this is an envelope attribute and refers to its users,
      disclosure of the envelope recipient list. Disclosure of other
      recipients is in Internet mail done via the To:, cc: and this bcc:



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      header fields.  Not for general use.


2.2 Permanent MIME header field should not
      be used when sending a message through the net.  The use registrations


   Header name         Protocol
   -----------         --------
   MIME-Version        MIME      MIME version number
   Content-ID          MIME      Identify content body part
   Content-Description MIME      Description of message body part
   Content-Transfer-Encoding
                       MIME      Content transfer encoding applied
   Content-Type        MIME      MIME content type
   Content-Base        MIME      Base to be used for resolving
                                 relative URIs within this
      header field in transmission content
                                 part.
   Content-Location    MIME      URI for retrieving a body part
   Content-features    MIME      Indicates content features of a message can cause several
      robustness
                                 MIME body part
   Content-Disposition MIME      Intended content disposition and interoperability problems.


2.2.50 Content-Conversion: header

   Header name:
      Content-Conversion

   Description:
      Variant
                                 file name
   Content-Language    MIME      Language of 'Conversion:'

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard




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   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Non-standard variant message content
   Content-Alternative MIME      Alternative content available
   Content-MD5         MIME      MD5 checksum of 'Conversion:' with the same values.


2.2.51 Content-Class: header content

                                Figure 2


2.2.1 Header name:
      Content-Class field: MIME-Version

   Description:
      Hierarchical content classification
      MIME version number

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Type information of the content in some class hierarchy.  Class
      hierarchies are commonly used to classify data structures in
      software development.


2.2.52 Content-SGML-Entity: header

   Header name:
      Content-SGML-Entity

   Description:
      SGML entity information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 4)





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   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt         February 2004


   Related information:
      Information from the SGML entity declaration corresponding
      An indicator that this message is formatted according to the
      entity contained in the body MIME
      standard, and an indication of the body part.


2.2.53 X-MIME-Autoconverted: header

   Header name:
      X-MIME-Autoconverted

   Description:
      In-transit message conversion information

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Information about conversion which version of this message on the path from
      sender to recipient, such as conversion between MIME encoding
      formats.


2.2.54 List-Digest: header is utilized.


2.2.2 Header name:
      List-Digest field: Content-ID

   Description:



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      URL for mailing list digest subscription
      Identify content body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 7)

   Related information:
      URL to use to get
      Specifies a subscription to the digest version Unique ID for one MIME body part of a
      mailing list from which this message was relayed.


2.2.55 Mailing-List: header the content of a
      message.


2.2.3 Header name:
      Mailing-List field: Content-Description

   Description:
      Mailing list information
      Description of message body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Non-standard precursors to List-ID and List-Post.
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 8)






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2.2.56 X-Mailing-List: header         February 2004


   Related information:
      Description of a particular body part of a message, for example a
      caption for an image body part.


2.2.4 Header name:
      X-Mailing-List field: Content-Transfer-Encoding

   Description:
      Mailing list information
      Content transfer encoding applied

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 6)

   Related information:
      Non-standard precursors to List-ID and List-Post.


2.2.57 List-Software: header
      Coding method used in a MIME message body part.


2.2.5 Header name:
      List-Software field: Content-Type

   Description:
      Mailing list software information
      MIME content type

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2045.txt (section 5)

   Related information:
      Information about
      Format of content (character set etc.) Note that the software used values for
      this header field are defined in different ways in RFC 1049 and in a mailing list expander



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      through which this message has passed.  Non-standard,         February 2004


      MIME (RFC 2045), look for the 'MIME-version' header field to
      understand if Content-Type is to be interpreted according to RFC
      1049 or according to MIME. The MIME definition should be used in
      generating mail. RFC 1049 has been
      considered 'historic' status.  RFC 1766 defines
      a parameter 'difference' to this header field. Various other
      Content-Type define various additional parameters. For example,
      the parameter 'charset' is mandatory for all textual
      Content-Types. See also: RFC 1049,  RFC 1123: 5.2.13,  RFC 1766:
      4.1.


2.2.6 Header field: Content-Base

   Description:
      Base to be used for resolving relative URIs within this content
      part.

   Applicable protocol:
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      standards-track

   Author/change controller:
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.rfc-editor.org/rfc/rfc2110.txt

   Related information:
      Base to be used for inclusion in RFC2369.


2.2.58 List-URL: header resolving relative URIs within this content
      part.


2.2.7 Header name:
      List-URL field: Content-Location

   Description:
      URL
      URI for mailing list information retrieving a body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track






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   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2110.txt

   Related information:
      Contains URL where information of various kinds about the mailing
      list from
      URI using which the content of this message body-part part was relayed.


2.2.59 X-Listserver: header retrieved,
      might be retrievable, or which otherwise gives a globally unique
      identification of the content.


2.2.8 Header name:
      X-Listserver field: Content-features

   Description:
      List server software information
      Indicates content features of a MIME body part

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):



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      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2912.txt (section 3)

   Related information:
      Information about the server and software
      The 'Content-features:' header can be used in to annotate a mailing list
      expander through which this message has passed.  Warning:
      'Listserv' is MIME body
      part with a trademark and should not be used for other than
      the 'Listserv' product.  Use, instead the 'List-Software' header
      field.  Non-standard.  Recommended media feature expression, to use 'List-Software' instead.


2.2.60 X-List-Host: header indicate features of the
      body part content. See also: RFC 2533, RFC 2506, RFC 2045.


2.2.9 Header name:
      X-List-Host field: Content-Disposition

   Description:
      List server software information
      Intended content disposition and file name

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      experimental




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   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc2183.txt

   Related information:
      Information about the server and software used in
      Whether a mailing list
      expander through which this message has passed.  Warning:
      'Listserv' MIME body part is a trademark and should not to be used shown inline or is an
      attachment; can also indicate a suggested filename for other than
      the 'Listserv' product.  Use, instead the 'List-Software' header
      field.  Non-standard.  Recommended to use 'List-Software' instead.


2.2.61 Fcc: header when
      saving an attachment to a file.


2.2.10 Header name:
      Fcc field: Content-Language

   Description:
      File for copy
      Language of message




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   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc3282.txt

   Related information:
      Name of file
      Can include a code for the natural language used in which a copy message,
      e.g. 'en' for English. Can also contain a list of this languages for a
      message is stored.


2.2.62 Speech-Act: header containing more than one language.


2.2.11 Header name:
      Speech-Act field: Content-Alternative

   Description:
      Speech act categorization of message
      Alternative content available

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt

   Related information:
      Speech act categoriztion of a message.  Examples of speech acts
      are Question, Idea, More, Promise, Sad, Happy, Angry, Summary,
      Decision.


2.2.63
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status: header

   Header name:
      Status
      work-in-progress




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   Description:
      Message status in delivery system

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)

   Status:
      non-standard         February 2004


   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt
      http://www.rfc-editor.org/rfc/rfc3297.txt

   Related information:
      This field is used by some mail delivery systems to indicate
      Information about the
      status media features of delivery alternative content
      formats available for this message when stored.  Common values of
      this field are: U message is not downloaded and not deleted.  R
      message is read or downloaded.  O message is old but not deleted.
      D to be deleted.  N new (a new message also sometimes is
      distinguished by not having any 'Status:'  header field.
      Combinations of these characters can occur, such as 'Status: OR'
      to indicate that a message is downloaded but not deleted.  Non-
      standard, should never appear in mail in transit.


2.2.64 X-No-Archive: header the current message.


2.2.12 Header name:
      X-No-Archive field: Content-MD5

   Description:
      Do not archive publicly
      MD5 checksum of content

   Applicable protocol:
      mail (http://www.rfc-editor.org/rfc/rfc2822.txt)
      MIME (http://www.rfc-editor.org/rfc/rfc2045.txt)

   Status:
      non-standard
      standards-track

   Author/change controller:
      Unknown  (mailto:xxxx@ietf.org)
      IETF  (mailto:iesg@ietf.org)
      Internet Engineering Task Force.

   Specification document(s):
      http://www.ietf.org/internet-drafts/draft-palme-mailext-headers-
      06.txt



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      http://www.rfc-editor.org/rfc/rfc1864.txt

   Related information:
      Do
      Checksum of content to ensure that it has not archive this message in publicly available archives. been modified.


3. IANA considerations

   This specification provides an initial registration registrations of mail and MIME
   headers in the two registries "Permanent Message Header Field Registry", defined by
   Registration procedures for message
   headers [1]:

   o  IANA registry for normative message headers, and

   o  IANA registry for provisional message headers. header fields [1].

4. Security considerations

   No security considerations are introduced by this specification
   beyond those already inherent in the use of message headers.

5. Acknowledgements

   Most of the information in this document has been derived from Jacob



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   Palme's work in RFC 2076 [8] and subsequent updates [20].

   The author authors also gratefully acknowledges acknowledge the contributions of: Mark
   Nottingham, [[[...]]]

References

   [1]   Klyne, G., Nottingham, M. and J. Mogul, "Registration
         procedures for message headers", Mar 2002,
         <http://search.ietf.org/internet-drafts/draft-klyne-msghdr-
         registry-04.txt>. Oct 2003, <http://
         www.ietf.org/internet-drafts/
         draft-klyne-msghdr-registry-07.txt>.

   [2]   Alvestrand, H., Jordan, K. and J. Romaguera, "Rules for
         downgrading messages from X.400/88 to X.400/84 when MIME
         content-types are present in the messages", RFC 1496, August
         1993.

   [3]   Costanzo, A., Robinson, D. and R. Ullmann, "Encoding Header
         Field for Internet Messages", RFC 1505, August 1993.

   [4]   Alvestrand, H., "Tags for the Identification of Languages", RFC
         1766, March 1995.

   [5]   Myers, J. and M. Rose, "The Content-MD5 Header Field", RFC
         1864, October 1995.



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   [6]   Freed, N. and N. Borenstein, "Multipurpose Internet Mail
         Extensions (MIME) Part One: Format of Internet Message Bodies",
         RFC 2045, November 1996.

   [7]   Freed, N. and N. Borenstein, "Multipurpose Internet Mail
         Extensions (MIME) Part Two: Media Types", RFC 2046, November
         1996.

   [8]   Palme, J., "Common Internet Message Headers", RFC 2076,
         February 1997.

   [9]   Palme, J. and A. Hopmann, "MIME E-mail Encapsulation of
         Aggregate Documents, such as HTML (MHTML)", RFC 2110, March
         1997.

   [10]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
         Levels", BCP 14, RFC 2119, March 1997.

   [11]  Kille, S., "MIXER (Mime Internet X.400 Enhanced Relay): Mapping
         between X.400 and RFC 822/MIME", RFC 2156, January 1998.

   [12]  Moore, K.,  Troost, R. and S. R., Dorner, S. and K. Moore, "Communicating



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         Presentation Information in Internet Messages: The Content-
         Disposition
         Content-Disposition Header Field", RFC 2183, August 1997.

   [13]  Fajman, R., "An Extensible Message Format for Message
         Disposition Notifications", RFC 2298, March 1998.

   [14]  Baer, J. and G.  Neufeld, G. and J. Baer, "The Use of URLs as Meta-Syntax for
         Core Mail List Commands and their Transport through Message
         Header Fields", RFC 2369, July 1998.

   [15]  Parsons,  Vaudreuil, G. and G. Vaudreuil, Parsons, "Voice Profile for Internet Mail
         - version 2", RFC 2421, September 1998.

   [16]  Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, April
         2001.

   [17]  Resnick, P., "Internet Message Format", RFC 2822, April 2001.

   [18]  Klyne, G., "Indicating Media Features for MIME Content", RFC
         2912, September 2000.

   [19]  Chandhok, R. and G. Wenger, "List-Id: A Structured Field and
         Namespace for the Identification of Mailing Lists", RFC 2919,
         April
         March 2001.

   [20]  Palme, J., "Common Internet Message Header Fields", Internet



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         draft draft-palme-mailext-headers-06, November 2001,
         <http://search.ietf.org/internet-drafts/draft-palme-mailext-
         headers-05.txt>. <http://
         search.ietf.org/internet-drafts/
         draft-palme-mailext-headers-05.txt>.

   [21]  <http://www.ninebynine.org/IETF/Messaging/HdrRegistry/Intro.html>


Author's Address  <http://www.ninebynine.org/IETF/Messaging/HdrRegistry/
         Intro.html>


Authors' Addresses

   Graham Klyne
   Clearswift Corporation
   MIMEsweeper Group
   1310 Waterside
   Arlington Business Park
   Theale, Reading  RG7 4SA
   Nine by Nine
   UK

   EMail: GK-IETF@ninebynine.org
   URI:   http://www.ninebynine.net/









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   Jacob Palme
   Stockholm University/KTH
   Forum 100
   Kista  S-164 40
   Sweden

   Phone: +44 11 8903 8903 +46-8-16 16 67
   EMail: Graham.Klyne@MIMEsweeper.com jpalme@dsv.su.se

Appendix A. Revision history

   [[[Please remove this section on final publication]]]

A.1 draft-klyne-hdrreg-mail-02

   02d 19-Feb-2004:

      *  Incorporated small changes to specific header field
         descriptions, suggested by Jacob.

   02c 18-Feb-2004:

      *  Separated Mail and MIME header fields.

      *  Corrected specification reference for MIXER headers (RFC 2156).

      *  Changed applicable protocol for MIME header fields.

      *  Other smaller corrections.

   02b 17-Feb-2004:

      *  Removed provisional mail header registrations from this
         document.

   02a 05-Aug-2002:

      *  Added Jacob Palme as co-editor.


A.2 draft-klyne-hdrreg-mail-01

   01c 05-Jun-2002:

      *  Minor editorial.






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   01b 10-May-2002:

      *  Updated some contact information.

      *  Regenerated registry tables with revised software.

   01a 08-May-2002:

      *  Revised change controller information in line with registry
         specification.

      *  Cleaned up some table layout.


A.2


A.3 draft-klyne-hdrreg-mail-00

   00c 05-May-2002:




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      *  Added data for permanent and provisional registries.

   00b 01-May-2002:

      *  Revised form of registry entry content. (Auto-generated from
         RDF data.)

   00a 22-Jan-2002:

      *  Document initially created.


Appendix B. TODO:

   [[[Please remove this section on final publication]]]

   o  Review source document information for provisional registry
      entries.

   o  Select appropriate email address for provisional entries with
      unknown change controller.  (Use mailing list for announcing new
      proposals?) format of header descriptions: may want to make this more
      compact.















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Intellectual Property Statement

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   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
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Full Copyright Statement

   Copyright (C) The Internet Society (2002). (2004). All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
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   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
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   The limited permissions granted above are perpetual and will not be
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   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION



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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.


Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.











































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----